Improved process for washing polyester materials

ABSTRACT

A soil, anti-redeposition agent for use in laundry applications is disclosed, which agent comprises a synergistic mixture of polyvinylpyrrolidone and polyvinyl alcohol.

Berni et al.

IMPROVED PROCESS FOR WASHING POLYESTER MATERIALS Inventors: Rene P. Berni, Oradell, N.J.;

Richard A. Grifo, Easton, Pa.

Related U.S. Application Data Division of Ser. No. 58,647, July 27, 1970, Pat. No. 3,689,435.

U.S. Cl 8/137, 252/89, 252/117, 252/152, 252/524, 252/542 1m. c| osh 3/00 Nov. 13, 1973 [58] Field of Search 252/89, 110, 117, 252/132, 135, 524, 542; 8/137 [56] References Cited UNITED STATES PATENTS 3,000,830 9/1961 Fong et a1 232/117 Primary ExaminerMayer Weinblatt Attorney-Walter C. Kehm et a1.

[ ABSTRACT A soil, anti-redeposition agent for use in laundry applications is disclosed, which agent comprises a synergistic mixture of polyvinylpyrrolidone and polyvinyl alcohol.

5 Claims, No Drawings IMPROVED PROCESS FOR WASHING POLYESTER MATERIALS This is a division of application Ser. No. 58,647, filed July 27,1970 now U.S. Pat. No. 3,689,435.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to soil anti-redeposition agents in laundry procedures and in particular to use of a mixture of polyvinylpyrrolidone and polyvinyl alcohol therefor.

2. Description of the Prior Art It is well known in the art that a successful washing operation involves two separate factors, i.e., (a) the removal of dirt from the textile material and (b) keeping the soil suspended in the medium so that it will not be re-deposited on the textile. In general aqueous washing media containing soap fulfill both of these criteria as soap not only is a good soil remover but also keeps the removed soil in suspension so that little re-deposition takes place. However, the present trend is toward the use of anionic synthetic detergents such as the alkyl benzene sulphonates since these agents can be used in hard water areas as their detersive power is not decreased by the presence of calcium and magnesium ions. However, these anionic detergents have the disadvantage that their suspending power is poor. Whereas they are very effective from the standpoint of removing soil they are not so effective in preventing re-deposition and so cotton fabrics washed with such agents will be grayer than when using soap. In order to overcome this disadvantage, various soil suspending agents are commonly added to the anionic detergents.

One of the most commonly used agents is polyvinyl alcohol. Other agents which have been used are sodium carboxymethyl cellulose and polyvinylpyrrolidone. Mixtures of sodium carboxymethyl cellulose and polyvinyl alcohol as well as sodium carboxymethyl cellulose and polyvinyl pyrrolidone have also been employed. See for example U.S'. Pat. Nos. 3,000,830 3,254,028, 3,284,364 and 3,318,186. i

The mechanisms by which the combination of soilsuspending agents function .in the washing baths to inhibit the redeposition' of soil upon the fabric have not SUMMARY OF THE INVENTION It is accordingly one object of the present invention to provide novel soil anti-redeposition compositions.

A further object of the invention is to provide procedures for use of these compositions in washing and laundry procedures.

A still further object is to provide a synergistic mixture of polyvinylpyrrolidone and polyvinyl alcohol useful as a soil anti-redeposition composition.

Other objects and advantages of the present invention will become apparent as the description thereof proceeds.

In satisfaction of the foregoing objects and advantages, there is provided by the present invention an agueous detergent composition containing a synergistic mixture of polyvinylpyrrolidone and polyvinyl alcohol in soil-suspending amounts. Also provided are procedures for use of these compositions in laundry applications in providing increased whitening effects.

DESCRIPTION OF PREFERRED EMBODIMENTS In accordance with the present invention, it has been discovered that a mixture of polyvinylpyrrolidone and polyvinyl alcohol as a soil anti-redeposition composition possesses greater properties for this purpose than either component exhibits alone. Accordingly, it was found that the mixture exhibits a synergistic effect when present in soil suspending amounts. Thus it has now been found that this synergistic mixture has exceedingly useful soil-suspending properties when added to aqueous washing media.

The synergistic mixture may comprise from about 10 to 90 percent by weight of the polyvinylpyrrolidone to about 90 to 10 percent by weight of the polyvinyl alcohol. A preferred mixture, however, consists of about 50 weight percent of each component.

The polyvinylpyrrolidone component employed in the invention may be generally those polymers known in the art. As is well known in the art, polyvinylpyrrolidone is not a single, individual compound but may be obtained in almost any degree of polymerization. The degree of polymerization is most easily exbeen determined exactly .in view of the apparent cosodium carboxymethylcellulose or the like, this material is believed to'be primarily effective in preventing deposition of soil upon cellulosic fabrics by its adsorption on the surface of the fabric. In contrast thereto, the polyvinylpyrrolidone is believedto be adsorbed to an appreciable extent on carbon soil, but is not adsorbed substantially on cotton from a detergent solution. Thus,

the polyvinylpyrrolidone is much more effective in preventing the flocculation and precipitation of carbon in aqueous suspension than sodium carboxymethylcellulose. l v i The present invention provides a novel soil antiredeposition synergistic mixture which provides excellent results in washing or laundry procedures.

pressed in terms of average molecular weight. Although this invention comprises in its broad aspect the use of polyvinylpyrrolidone having any degree of polymerization and which is soluble in water at least to the extent of about 0.001% to about 0.1%, itis to be understood that nota ll the polymers possess the same degree of effectiveness. Thus, polyvinylpyrrolidones having an average molecular weight from about 5,000 to 100,000 and preferably 15,000 to about 40,000 exhibit maximum soil-suspending activity. For this reason it is preferred to use a polyvinylpyrrolidone of such molecular weight range in the washing operations- The polyvinyl alcohol employed is also well known in the art andmay prepared from polyvinyl acetate or similar polyvinyl esters by replacement of acetate groups .by hydroxyl groups and this chemical reaction is commonly known as hydrolysis in the art. The polyvinyl alcohol is often identified by its viscosity, and percent hydrolysis or percent ester content. The polyvinyl alcohol may be of low, medium or high viscosity and may be selected from the range of about 1.8 to 65, and preferably up to 6 centipoises. Reference to centipoises herein refers to determinations made in a 4% aqueous solution at 20C. The product may contain minor amounts of polyvinyl acetate such as up to about 30% by weight and preferably from about to 30% ester content. The degree of hydrolysis is thus usually within the range from about 70 to 100%. Suitable examples are polyvinyl alcohol which has a viscosity of 4 to 6 cps. with about 12% ester (88-89% hydrolysis); and polyvinyl alcohols having a viscosity of 21 25 cps. or 35-45 cps. with about 12% ester.

It is preferred to employ polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of about 10 to by weight. This material exhibits maximum stability upon storage of the composition at elevated temperature resulting in maximum soilsuspending power for the composition. It may be prepared by any suitable manner such as by control of the degree of polymerization and alcoholysis of the polyvinyl acetate to produce a product of the above characteristics. The above viscosity range correspondsto an approximate weight average degree of polymerization of about to I00. Examples thereof are polyvinyl alcohols having a viscosity of 2.34 cps. and 22.3% polyvinyl acetate; 1.88 cps. and 19.6% ester; 1.98 cps. and 29.4% ester; 2.38 cps. and 12.8% ester; and the like.

In applying this invention in practice the synergistic mixture may be dispersed into the aqueous washing medium in a concentration from about 0.001 to about l.0%-the higher proportions giving the greater degree of protection against soil redeposition. It is obvious that the proportion of the mixture can be higher than the above range but in general increasing the concentration above 1.0% gives little if any added protection. If desired, the mixture can be incorporated with the detergent so as to form a composition which on dissolving in water furnishes the desired washing medium. To this end, the detergent is mixed with about 2 to 10% of the synergistic mixture.

In carrying out washing operations in accordance with this invention, the fabric or other textile material is agitated in the usual manner preferably at elevated temperatures as commonly used in laundries with the aqueous media containing the synergistic mixture and the detergent. As the detergent, one may'use any of the materials commonly used for Washing'purposes.

The detergent may be, for example, of the anionic or non-ionic types. In the first category are included ordinary soaps, that is, sodium or potassium salts of the higher fatty acids, or, usually, mixtures of higher fatty acids are derived from naturally-occurring oils and fats. Also included in the anionic category are the detergents of the sulphonate or sulphate type. As well known in the art, a multitude of such materials are available, including the alkyl (C -C sulphates, the alkyl (C -C sulphonates, the alkyl (C -C aromatic sulphonates, the monoor di-alkyl (C -C esters of sulphosuccinic acid, sulphonated or sulphated amides of the higher fatty acids such as N-sulphoethyl stearadium undecyl sulphonate, sodium dodecyl sulphonate, sodium tridecyl sulphonate, sodium tetradecyl sulphonate, sodium pentadecyl sulphonate, sodium hexadecyl sulphonate, sodium octadecyl sulphonate, sodium oleyl sulphonate, sodium salt of di-octyl sulpho-succinate, sodium octyl benzene sulphonate, sodium nonyl benzene sulphonate, sodium decyl benzene sulphonate, sodium undecyl benzene sulphonate, sodium dodecyl benzene sulphonate, sodium tridecyl benzene sulphonate, sodium tetradecyl benzene sulphonate, sodium pentadecyl benzene sulphonate, sodium hexadecyl benzene sulphonate, sodium heptadecyl benzene sulphonate, sodium octadecyl benzene sulphonate, sodium tri (isopropyl) benzene sulphonate, sodium tri (isobutyl) benzene sulphonate, sodium tri (isopropyl) naphthalene sulphonate, sodium tri (isobutyl) naphthalene sulphonate, and so forth. The commerically available detergents are generally not pure compounds but are mixtures of homologous compounds and are quite satisfactory. Thus for example, the sodium alkyl benzene sulphonate wherein the alkyl group contains 12 to 18 carbon atoms is a well known detergent. Others are: a mixture of sodium alkyl sulphates consisting mostly of sodium lauryl sulphate; a mixture of sodium alkyl phenol sulphonates wherein the alkyl group contains 12 to 18 carbon atoms; and a mixture of sodium alkyl sulphonates wherein the alkyl group contains 10 to 18 carbon atoms. As non-anionic detergents one may employ polyalkylene glycol esters, ethers and thioethers of the following types:

RS(--C I-I O),,I-I wherein the Rs represent long chain alkyl radicals of eight to 12 carbon atoms and n is an integer from about 4 to 12. Other nonanionic detergents are the long-chain fatty acid esters of anhydrosorbitol, or the polyethylene glycol addition products of such esters. It is evident that the particular detergent used is not critical except that one should be chosen which is generally useful in emulsifying and detergent applications.

The amount of active detergent substituent of a cleaning formulation will also vary within wide limits and will depend upon such factors as specified above and in particular the purposefor which the formulation is intended. It has been found that from about 5 to about 95% of the total weight may advantageously be the detergent constituent with the preferred narrower commercial limits being from about 20 to about 35% by weight.

The cleaning formulation may also have added to it various other special additives such as hydrotapes or coupling agents, building agents and fillers including soda ash, sodium sesquicarbonate, sodium tetrapyrophosphate, sodium tripolyphosphate, sodium silicate, sodium metasilicate, borax and the like. In addition, non-alkaline inorganic salts such as sodium sulfate, sodium chloride and sodium bicarbonate may be added as well as scouring abrasives such as diatomaceous earth or ground pumice, bentonite and various other clays and clay-like substances. The amount of such special purpose additives or builders will naturally vary within wide limits or'may even be omitted entirely. However, it has been found that amounts of from about 1% up to as high as by weight based on the formulation weight may be added depending upon the purpose for which the formulation is intended.

thereto.

The soil redeposition inhibitors of this invention may be incorporated into bar soaps for cleaning, laundering and scrubbing; scouring powders for more abrasive purposes; powdered or flaked soaps and synthetic organic non-soap detergents for laundry and general cleaning; for dry cleaning detergents and agents; and other synthetic detergents in liquid form.

In accordance with the present invention, it has been j discovered that a detergent composition comprising in I combination a water-soluble detergent such as a higher alkyl benzene sulfonate detergent and a mixture of a water-soluble polyvinyl alcohol soil-suspending agent and a water-soluble polyvinylpyrrolidone polymeric soil-suspending agent, the proportions thereof being effective in combination as more particularly described herein, exhibits an enhanced degree of soil suspension, particularly during washing of white fabrics. A synergistic improvement in soil suspension is achieved by this combination of soil-suspending agents with detergents as evidenced by a superior whiteness of the washed fabrics as compared to the expected effects f or in aqueous slurry containing a minor amount of Na SO v 2. 35% Sodium Tripolyphosphate 3. 5% Na SiO 4. 35% Na SO B. Nonionic Composition:

l. lgepal CO-630-N0nylphenol +9 ethylene oxide units; 2. Sodium Tripolyphosphate; 3. 5% Na SiO 4. 40% Na SO The synergistic mixture was prepared in the proportions indicated below and evaluated for ability to increase whiteness with the anionic and nonionic detergent compositions described above in standard washing operations employing automatic washing machines. The synergistic soil anti-redeposition agent was present in an amount of 0.5 weight percent based on the detergent composition weight. These are set forth in the fol- 20 lowing table wherein PVP is polyvinylpyrrolidone and A itps telaqh l- TABLE.-Anti-redeposition Evaluation of Mixtures of PVP and PVA whiteness 1 Anionic formula Nonionic formula BIG BIG D/C D/C Cone. Spun with without with without Product (percent) Cotton dacron finish finish Cotton Dacron finish finish PVP 0.25 55.9 56.3 56.4 65.4 56.0 49.6 58.8 66.6 PVA 0.25 Y Y PVP 0.375 58.5 55.6 55.9 65.7 PVA 0.125 PVP 0.125 57.3 53.2 58.0 64.2 PVA 0.375 PVP 0.375 56.4 51.9 56.0 64.9 PVA 0.125 PVP 0.25 56.0 55.7 55.4 65.3 PVA 0.25

Whiteness= Green filter reflectance minus 4X green reflectance f lter reflectance.

said mixtures. The expected value for any mixture can be calculated by averaging or summing the two independent effects resulting from the use of these agents individually. The reference to the water-soluble soilsuspending agents or similar expression is intended torefer to their solubility or dispersibility in aqueous detergent solutions and the property of these materials for inhibiting the deposition of soil from a detergent solution upon the fabric and is not limited to any specific mechanism for producing such effect.

The following examples are presented to illustrate the invention but it is not to be considered as limited EXAMPLE The synergistic mixture of this invention was tested for its anti-redeposition properties using aqueous detergent compositions of both the anionic and nonionic types of the proportions listed hereinafter.

A. Anionic Composition:

1. 25% Ultrawet 60-K-a linear C -alkyl-benzene sulfonate (laurylbenzene sulfonate), 60% active The invention has been described hereinabove with reference to certain preferred embodiments. However,

it is not to be considered as limited thereto as obvious tion-consisting essentially of water, a water-soluble detergent, and a soil suspending mixture of water-soluble polyvinylpyrrolidone and a water-soluble polyvinyl alcohol product in the proportions of from about 3:l to 1:3 by weight, respectively, said polyvinylpyrrolidone having an average molecular weight of from about 15,000 to about 40,000 said polyvinyl alcohol product having a viscosity, measured in a 4% aqueous solution at 20C, in the range of from about 1.8 to about 65 centipoises and a polyvinyl acetate content of from about 10% to about 30% by weight based on the total weight of said polyvinyl alcohol product, said mixture being employed in an amount within the range of from about 2% to about 10% by weight of said detergent, whereby said aqueous solution effectively removes soil from the polyester textile material through the action of the detergent, the synergistic polyvinyl pyrrolidone and polyvinyl alcohol mixture being effective as a soilsuspending agent, inhibiting the redeposition of soil from said wash solution back onto the material being washed, thus enhancing the whiteness and cleanliness of the washed material.

2. The process of claim 1 in which said polyvinylpyrrolidone and said polyvinyl alcohol are present in a proportion of about 1:1 by weight.

poises. 

2. The process of claim 1 in which said polyvinylpyrrolidone and said polyvinyl alcohol are present in a proportion of about 1:1 by weight.
 3. The process of claim 1 in which the polyvinylpyrrolidone/polyvinyl alcohol ratio is about 3:1, respectively, by weight.
 4. The process of claim 1 in which the polyvinylpyrrolidone/polyvinyl alcohol ratio is about 1:3, respectively, by weight.
 5. The process of claim 1 in which said polyvinyl alcohol has a viscosity of from about 1.8 to about 6 centipoises. 